JPH0117044B2 - - Google Patents

Abstract

1. Method for cooling of the ash which, through overflow tubes, is discharged from a fluidized bed combustor into an ash cooler provided with distributor plate and heat-exchange surfaces characterized by the ash which on load reduction in the fluidized bed combustor is fluidized by a fluidizing agent supplied and in case of continuous operation of the fluidized bed combustor on disconnection of the fluidizing agent supply is distributed in bulk over the heat-exchange surfaces.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention is a swirl bed type combustion apparatus equipped with an ash cooler for cooling ash discharged from a swirl bed, and the ash cooler includes an aeration bed and a heat exchanger. The present invention relates to a swirl bed combustion device formed.

In known swirl bed combustion devices of this type, the ash cooler is designed as an open-surface cooler or as a swirl bed cooler. However, all of these known ash coolers are designed so that they can be used economically only over a limited load range.

When an ash cooler used in a swirl bed combustion apparatus is designed in this way, a substantial distinction must be made between two conditions of use. The first usage state refers to a state where the device is used continuously with the same load. In this state of use, the height of the swirl bed must be kept constant during relatively long periods of operation. The ash generated during this period must then be removed from the swirl bed and cooled in an ash cooler before being transported. The second use condition refers to the condition created by removing the swirl bed material from the swirl bed combustion device at reduced load. The second use condition differs from the continuous use case described above in that a large amount of ash corresponding to the rate of change in load must be removed and cooled over a relatively short period of time. The amount of ash produced in the second state of use can be many times the amount of ash produced in the case of continuous use. It must be possible to cool such a large amount of ash by passing it through an ash cooler.

The purpose of the invention is to keep the cost and energy required for cooling the ash as low as possible, and
The object of the present invention is to control the above-mentioned two usage conditions with one cooling system.

To achieve the above object, the present invention provides a swirl bed combustion device of the initially mentioned type, in which the ash cooler is provided with a disconnectable supply line for supplying a swirl medium, the swirl bed combustion installed at the level of the vortex bed of the device and connected to the vortex bed through an overflow pipe, and at least a portion of the heat exchange surface of the ash cooler heat exchanger is below the overflow pipe. It is an object of the present invention to provide a swirl bed combustion device characterized by being disposed at a low position. According to the present invention, when the swirled bed combustion device according to the present invention is operated continuously, the supply of the swirling medium to the ash cooler is stopped, and the heat of the ash cooler is transferred from the swirled bed combustion device to the ash cooler. transporting the ash as a free deposit across the heat exchange surfaces of the exchanger and fluidizing the ash in the ash cooler by supplying a swirling medium when the load of the swirl bed combustion apparatus decreases; The characteristic ash cooling method can be implemented.

According to the invention, one and the same ash cooler can also be used as an open surface cooler and as a swirl bed cooler. For “download” operating conditions, swirl bed coolers are used; however, the high heat transfer coefficient of swirl bed coolers allows the practical size of the ash cooler to be increased. be. For continuous operation, the swirl bed cooler can be used as an open surface cooler, which allows the energy required for cooling to be kept to a minimum.

The invention will now be described in detail with reference to the accompanying drawings, which illustrate embodiments of the invention.

The swirl bed type combustion device has a swirl bed 2 on top of the ventilation bed 3.
The combustion chamber 1 is provided with a swirl bed combustion chamber 1, which is only partially shown, with a Combustion air, which acts as a swirling medium, is supplied to the air box 4 and blown into the swirling bed 2 through a number of small holes in the ventilation bed 3. A waste heat boiler (not shown) with heating surfaces is connected to the swirl bed combustion chamber 1 . It is also possible to provide additional heating surfaces in the free space of the combustion chamber 1 in and above the swirl bed 2 . Further, the side wall of the swirl bed combustion chamber 1 may be formed of a cooling pipe.

The ash produced during combustion is removed from the swirl bed 2 and conveyed to an ash cooler 5. The ash cooler 5 is equipped with a take-off pipe 6 in which a bucket wheel 7 is provided as a transport mechanism. The heat contained in the ash is extracted through the heat exchange surface of a heat exchanger 8 which extends into the ash cooler 5 as a tube bundle.

The ash cooler 5 is equipped with a ventilation bed 10 above the supply line 9 of the swirling medium. A shut-off flap 11 is provided in the supply line 9, the shut-off flap 1
By operating 1, the swirling medium can be supplied or stopped. In the illustrated example, air is used as the swirling medium. The upper closure of the ash cooler 5 is connected to the swirl bed combustion chamber 1 via a passage 12 . A shutoff flap 13 is provided in the passage 12.

The ash cooler 5 is mounted at approximately the same level as the swirl bed 2 of the swirl bed combustion chamber is located. Therefore, it is preferable that the ventilation bed 10 of the ash cooler 5 is positioned slightly lower than the ventilation bed 3 on the swirl bed 2 side. The ash cooler 5 is connected to the swirl bed 2 via one or more overflow pipes 14 . The ash enters the ash cooler 5 from the swirl bed 2 through this overflow pipe 14. The overflow pipe 14 is installed on the wall of the swirl bed combustion chamber 1 at a predetermined height above the ventilation bed 3. The height is set lower than the height of the vortex layer 2 under load. On the other hand, at least a part of the heat exchange surface of the heat exchanger 8 provided in the ash cooler 5 is located below the inlet where the overflow pipe 14 enters the ash cooler 5.

When the swirl bed combustion chamber is operated continuously, the ash cooler 5 is used as an open-surface cooler (see FIG. 2). In this case, the supply of swirling medium through the shutoff flap 11 arranged in the supply line 9 is interrupted. The shut-off flap 13 in the passage 12 between the ash cooler 5 and the swirl-bed combustion chamber 1 is also closed. Ash generated during continuous operation of the swirl bed combustion chamber is stored in an ash cooler 5.
flowing down and depositing in a free state while forming a deposition cone around the heat exchange surface of the heat exchanger 8,
It is cooled to the required temperature and then discharged through the take-out pipe 6 by rotating the bucket wheel 7.

When the load on the swirl bed combustion chamber decreases, the swirl bed 2
As the height of the ash falls, a correspondingly large amount of ash must be discharged. To cope with such operating conditions, the ash cooler 5 is used as a swirl bed cooler. By opening the shut-off flap 11 in the feed line 9, air as a swirling medium is blown into the ash cooler 5 through the ventilation bed 10. At the same time, the shut-off flap 13 in the channel 12 is opened and a gas-side connection is established between the ash cooler 5 and the swirl-bed combustion chamber 1.
Due to this special construction of the ash cooler 5 and the use of the special properties of the swirl bed, it is possible to use this swirl bed cooler according to the open tube principle. When the ash in the ash cooler 5 becomes fluid, the level of ash in the ash cooler 5 is in equilibrium with the level of the swirl bed 2 on the side of the swirl bed combustion chamber. Heat exchanger 8 in good heat transfer with the swirl bed
Since the usable surface area of the ash cooler 5 is increased, it is possible to cool a large amount of ash even if the volume of the ash cooler 5 is relatively small. Since the air acting as a swirling medium passes through the passage 12 and mixes with the combustion gas side of the swirl bed combustion chamber, losses on the air side are small, reducing the installation of a supplementary dust separation system that would otherwise be necessary. You can do it without needing it. The level of the swirl bed in the ash cooler 5 can be lowered by turning the bucket wheel 7 and discharging through the take-off pipe 6.

[Brief explanation of drawings]

FIG. 1 is a longitudinal cross-sectional diagram of a swirled bed combustion apparatus according to the present invention having an ash cooler configured as a swirled bed cooler, and FIG.
1 is a schematic cross-sectional diagram cut along the length of a swirl bed combustion apparatus in which an ash cooler is used as an open surface cooler; FIG. 1... Swirl bed type combustion chamber, 2... Swirl bed, 3...
Ventilation floor, 4... Air box, 5... Ash cooler, 6... Take-out pipe, 7... Basket wheel, 8... Heat exchanger, 9... Supply pipeline, 10...
Ventilation floor, 11...blocking flap, 12...passageway,
13...Shutoff flap, 14...Overflow pipe.

Claims (1)

[Scope of Claims] 1. A swirl bed type combustion apparatus equipped with an ash cooler 5 for cooling ash discharged from a swirl bed 2, the ash cooler 5 having a ventilation bed 10, a heat exchanger 8, and a heat exchanger 8. In the swirl bed type combustion equipment where the ash cooler 5 is installed,
is provided with a shutoff line 9 for supplying the swirl medium and is mounted approximately at the same level as the swirl bed 2 of the swirl bed combustion device and is connected to the swirl bed 2 via an overflow pipe 14. and that at least a portion of the heat exchange surface of the heat exchanger 8 of the ash cooler 5 is connected to the overflow pipe 14.
A swirl bed combustion device characterized by being located at a lower position. 2. The overflow pipe 14 is installed at a higher position than the ventilation bed 3 of the swirl bed 2, and this height position is lower than the height of the swirl bed 2 when the swirl bed combustion device is at a minimum load. A swirl bed combustion device according to claim 1. 3 Passage 1 that can be blocked by the upper closing part of the ash cooler 5
3. The swirl bed combustion apparatus according to claim 1, wherein the swirl bed combustion chamber 1 is connected to the swirl bed combustion chamber 1 at a position higher than the swirl bed 2 through the swirl bed combustion chamber 1.